U.S. patent number 8,416,534 [Application Number 12/828,103] was granted by the patent office on 2013-04-09 for disk drive with asymmetric tolerance ring.
This patent grant is currently assigned to Western Digital Technologies, Inc.. The grantee listed for this patent is Baekho Heo, Ryan J. Schmidt, Scott E. Watson. Invention is credited to Baekho Heo, Ryan J. Schmidt, Scott E. Watson.
United States Patent |
8,416,534 |
Heo , et al. |
April 9, 2013 |
Disk drive with asymmetric tolerance ring
Abstract
Described herein is a tolerance ring for a disk drive that
includes a substantially cylindrical body having outer surface. The
tolerance ring can be positioned between a rotational bearing and
an actuator for providing rotational movement of the actuator. The
tolerance ring can also include a contact member, positioned along
the outer surface, that protrudes outward from the outer surface.
The contact member can be connected to the outer surface by first
and second angulated arms that extend from the outer surface to the
contact member at different angles relative to the outer
surface.
Inventors: |
Heo; Baekho (San Jose, CA),
Watson; Scott E. (San Jose, CA), Schmidt; Ryan J. (Santa
Barbara, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Heo; Baekho
Watson; Scott E.
Schmidt; Ryan J. |
San Jose
San Jose
Santa Barbara |
CA
CA
CA |
US
US
US |
|
|
Assignee: |
Western Digital Technologies,
Inc. (Irvine, CA)
|
Family
ID: |
47999260 |
Appl.
No.: |
12/828,103 |
Filed: |
June 30, 2010 |
Current U.S.
Class: |
360/265.6 |
Current CPC
Class: |
G11B
5/4833 (20130101) |
Current International
Class: |
G11B
5/55 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Davis; David D
Claims
What is claimed is:
1. A disk drive comprising: an actuator assembly having a rotation
axis and being configured to rotate about the axis; a bearing
configured to provide rotational movement of the actuator assembly
about the axis; and a substantially cylindrical tolerance ring
having an internal wall and an external wall, the tolerance ring
being configured to engage the bearing along the internal wall and
having a contact member, for engaging the actuator assembly, along
the external wall, the contact member comprising a contact surface
protruding outward from the external wall, the contact surface
being connected to the external wall by two angulated walls
extending on opposing ends of the contact surface, wherein the two
angulated walls extend from the external wall to the contact
surface at different angles, and wherein the contact surface
extends in a direction that is substantially parallel to the
external wall.
2. The disk drive of claim 1, wherein the tolerance ring comprises
a bottom edge and a top edge, and the contact member is positioned
along the external wall closer to one of the bottom edge and the
top edge.
3. The disk drive of claim 2, wherein a first angulated wall of the
two angulated walls is positioned closer to the one of the bottom
edge and the top edge than a second angulated wall of the two
angulated walls.
4. The disk drive of claim 3, wherein the first angulated wall
extends from the external wall at a greater angle than the second
angulated wall.
5. The disk drive of claim 4, wherein the first angulated wall
extends from the external wall at an angle of from about 15.degree.
to about 45.degree..
6. The disk drive of claim 4, wherein the second angulated wall
extends from the external wall at an angle of from about 5.degree.
to about 35.degree..
7. The disk drive of claim 1, wherein the tolerance ring comprises
a plurality of contact members.
8. The disk drive of claim 7, wherein the plurality of contact
members are positioned circumferentially about the substantially
cylindrical tolerance ring.
9. The disk drive of claim 7, wherein the plurality of contact
members define an annular contact region about the external wall of
the tolerance ring.
10. The disk drive of claim 7, wherein the cylindrical ring defines
a ring axis, and the plurality of contact members are positioned at
different locations along the ring axis.
11. The disk drive of claim 1, wherein the bearing comprises a ball
bearing, and the contact member is positioned adjacent the ball
bearing when the tolerance ring is positioned between and engages
the bearing and the actuator assembly.
12. A tolerance ring for a disk drive, the tolerance ring
comprising: a substantially cylindrical body having an internal
wall and an external wall, the tolerance ring being configured to
be positioned about, and to engage along the internal wall, a
rotational bearing, the cylindrical body defining an axis; and a
contact member positioned along the external wall, the contact
member comprising a contact surface protruding outward from the
external wall such that the contact surface is spaced at a greater
radial distance from the axis than the external wall, the contact
surface being connected to the external wall by a first angulated
arm and a second angulated arm; wherein the first and second
angulated arms extend from the external wall to the contact surface
at different angles, and wherein the contact surface extends in a
direction that is substantially parallel to the external wall.
13. The tolerance ring of claim 12, wherein the first angulated arm
is positioned closer to one of a bottom edge of the ring and a top
edge of the ring than the second angulated arm, and the first
angulated arm extends from the external wall at a greater angle
than the second angulated arm.
14. The tolerance ring of claim 13, wherein the first angulated arm
extends from the external wall at an angle of from about 15.degree.
to about 45.degree..
15. The tolerance ring of claim 13, wherein the second angulated
arm extends from the external wall at an angle of from about
5.degree. to about 35.degree..
16. The tolerance ring of claim 12, wherein the tolerance ring
comprises a plurality of contact members.
17. The tolerance ring of claim 16, wherein the plurality of
contact members are positioned circumferentially about the
substantially cylindrical body.
18. The tolerance ring of claim 16, wherein the plurality of
contact members are positioned at different locations along the
axis.
19. The tolerance ring of claim 16, wherein the plurality of
contact members form two annular contact regions about the ring,
the two contact regions being spaced along the axis.
Description
BACKGROUND
Hard disk drives, (HDD) are often used in electronic devices, such
as computers, to record data onto or to reproduce data from a
recording media, which can be a disk having one or more recording
surfaces. The HDD also includes a head for reading the data on a
recording surface of the disk and for writing data unto one of the
surfaces. An actuator is provided for moving the head over a
desired location, or track of the disk.
The HDD includes a spindle motor for rotating the disk during
operation. When the disk drive is operated, and the actuator moves
the head over the disk, the head is floated a predetermined height
above the recording surface of the disk while the disk is rotated,
and the head detects and/or modifies the recording surface of the
disk to retrieve, record, and/or reproduce data from and/or onto
the disk.
When the HDD is not in operation, or when the disk is not rotating,
the head can be rotated by the actuator to a position such that the
head is not over the disk or the recording surfaces. In this
non-operational configuration, the head is "parked off" of the
recording surface of the disk.
BRIEF DESCRIPTION OF THE DRAWINGS
A general architecture that implements the various features of the
disclosure will now be described with reference to the drawings.
The drawings and the associated descriptions are provided to
illustrate embodiments of the disclosure and not to limit the scope
of the disclosure. Throughout the drawings, reference numbers are
reused to indicate correspondence between referenced elements.
FIG. 1 depicts a perspective view of a disk drive in accordance
with one embodiment.
FIG. 2 illustrates a top view of a disk drive in accordance with
one embodiment.
FIG. 3 illustrates a partial exploded view of an actuator in
accordance with one embodiment.
FIG. 4 illustrates a schematic cross-sectional view of a pivot
shaft and bearing.
FIG. 5 illustrates another schematic cross-sectional view of a
pivot shaft and bearing.
FIG. 6 illustrates a schematic view of a tolerance ring coupling an
actuator to a pivot shaft.
FIG. 7 illustrates another schematic view of a tolerance ring
coupling an actuator to a pivot shaft.
DETAILED DESCRIPTION
Referring now to FIG. 1, there is depicted an exploded perspective
view of a disk drive 10 according to embodiments described herein.
The disk drive 10 includes a head disk assembly (HDA) and a printed
circuit board assembly (PCBA). The head disk assembly includes a
disk drive housing having disk drive housing members, such as a
disk drive base 12 and a cover 14. The disk drive base 12 and the
cover 14 collectively house at least one disk 16. A single disk or
additional disks may be included in the disk drive.
The disk 16 includes an inner diameter (ID) 18 and an outer
diameter (OD) 20. The disk 16 further includes a plurality of
tracks on its recording surface, or face, for storing data. The
disk 16 may be of a magnetic recording type of storage device,
however, other arrangements (e.g., optical recording) may be
utilized. The head disk assembly further includes a spindle motor
22 for rotating the disk 16 about a disk rotation axis 24. The head
disk assembly further includes a head stack assembly 26 rotatably
attached to the disk drive base 12 in operable communication with
the disk 16. The head stack assembly 26 includes an actuator
28.
The actuator 28 includes an actuator body and at least one actuator
arm 32 that extends from the actuator body. Some embodiments
include multiple arms 32. Distally attached to the actuator arms 32
are suspension assemblies 34. The suspension assemblies 34
respectively support heads 36. The suspension assemblies 34 with
the heads 36 are referred to as head gimbal assemblies. The number
of actuator arms and suspension assemblies may vary depending upon
the number of disks and disk surfaces utilized.
The head 36 can include a transducer for writing and reading data.
The transducer can include a writer and a read element. In magnetic
recording applications, the transducer's writer may be of a
longitudinal or perpendicular design, and the read element of the
transducer may be inductive or magnetoresistive.
In optical and magneto-optical recording applications, the head may
also include an objective lens and an active or passive mechanism
for controlling the separation of the objective lens from a disk
surface of the disk 16. The disk 16 includes opposing disk
surfaces. In magnetic recording applications the disk surface
typically includes one or more magnetic layers. Data may be
recorded along data annular regions on a single disk surface or
both.
The head stack assembly 26 may be pivoted such that each head 36 is
disposed adjacent to the various data annular regions from adjacent
to the outer diameter 20 to the inner diameter 18 of the disk 16.
In FIG. 1, the actuator body includes a bore, and the actuator 28
further includes a pivot bearing cartridge 38 engaged within the
bore for facilitating the actuator body to rotate between limited
positions about an axis of rotation 40.
The actuator 28 can further include a coil support element 42 that
extends from one side of the actuator body opposite the actuator
arms 32. The coil support element 42 is configured to support a
coil 44. A VCM magnet 46 may be supported by the disk drive base
12. Posts may be provided to position the VCM magnet 46 in a
desired alignment against the disk drive base 12. A VCM top plate
48 may be attached to an underside of the cover 14. The coil 44 is
positioned, in some embodiments, between the VCM magnet 46 and the
VCM top plate 48 to form a voice coil motor for controllably
rotating the actuator 28.
The head stack assembly 26 can further include a flex cable
assembly 50 and a cable connector 52. The cable connector 52 can be
attached to the disk drive base 12 and is disposed in electrical
communication with the printed circuit board assembly. The flex
cable assembly 50 supplies current to the coil 44 and carries
signals between the heads 36 and the printed circuit board
assembly.
With this configuration, current passing through the coil 44
results in a torque being applied to the actuator 28. The actuator
28 includes an actuator longitudinal axis 64 which extends
generally along the actuator arms 32. A change in direction of the
current through the coil 44 results in a change in direction of the
torque applied to the actuator 28, and consequently, the
longitudinal axis 64 of the actuator arms 32 is rotated about the
axis of rotation 40. It is contemplated that other magnet, VCM
plate, coil and magnet support configurations may be utilized, such
as a multiple coil arrangements, single or double VCM plates and a
vertical coil arrangement.
The disk drive 10 can also include a latch 54. The latch 54 can
include a fixed portion 56 that is firmly coupled to the disk drive
base 12. The latch 54 further includes a latching portion that is
engagable with fixed portion 56 to limit rotational movement of the
actuator 28. Although the latch 54 is depicted as being located in
a corner of the base, the latch 54 could be located in other
portions of the disk drive and still perform its functions.
When the actuator 28 is rotated into the parked position, as
illustrated in FIG. 1, the actuator 28 can include a contact member
76, which can be located on the coil support element 42 or
elsewhere, that is configured to engage a crash stop 80 in order to
limit rotation of the actuator 28 away from the disk 16. The crash
stop 80 can be an integral part of the base 12, or the crash stop
80 can be connected to the base 12 via a fixation element 72. FIG.
1 depicts an axis of engagement 66 of the contact member 76 and the
crash stop 80 as being in line with the fixation element 72, but
other constructions are also permissible. A crash stop 80 can also
be provided to limit movement of the actuator 28 toward the ID 18
of the disk 16.
Data is recorded onto a surface of the disk in a pattern of
concentric rings known as data tracks. The disk surface is spun at
high speed by means of a motor-hub assembly. Data tracks are
recorded onto disk surface by means of the head 36, which typically
resides at the end of the actuator arm 32. One skilled in the art
understands that what is described for one head-disk combination
applies to multiple head-disk combinations.
The dynamic performance of the HDD is a major mechanical factor for
achieving higher data capacity as well as for manipulating the data
faster. The quantity of data tracks recorded on the disk surface is
determined partly by how well the head 36 and a desired data track
can be positioned relative to each other and made to follow each
other in a stable and controlled manner. There are many factors
that can influence the ability of HDD to perform the function of
positioning the head 36 and following the data track with the head
36. In general, these factors can be put into two categories; those
factors that influence the motion of the head 36; and those factors
that influence the motion of the data track. Undesirable motions
can come about through unwanted vibration and undesirable
tolerances of components.
During development of the HDD, the disk 16 and head 36 have
undergone reductions in size. Much of the refinement and reduction
has been motivated by consumer request and demand for more compact
and portable hard drives 10. For example, the original hard disk
drive had a disk diameter many times larger than those being
developed and contemplated.
Smaller drives often have small components with relatively very
narrow tolerances. For example, disk drive heads 36 are designed to
be positioned in very close proximity to the disk surface. Due to
the tight tolerances, vibration activity of the actuator arm 32
relative to the disk 16 can adversely affect the performance of the
HDD. For example, vibration of the actuator 28 can result in
variations in the spacing between the head element and media.
Additionally, irregular movement of the disk 16, or vibrations
caused by unbalanced rotations, can result in variations in the
spacing between the head element and the disk 16, or media.
In addition, as disk drive tracks per inch (TPI) increases,
sensitivity to small vibrations also increases. Small vibrations
can cause significant off-track and degraded performances. For
example, in many cases, variations in the spacing between the head
element and media can increase the off-track complications, and the
increase in TPI compounds the complications and likely gives rise
to data errors. These data errors can include both hard errors
during writing and soft errors during reading. Moreover,
vibration-induced errors become even more apparent as the actual
offset distances and overall components are reduced in size.
Each disk 16 is mounted on a rotatable hub 98 connected to the
spindle motor 22 and is secured to the rotatable hub by a disk
clamp 100, as illustrated in FIG. 2. Some disk drives 10 include a
plurality of disks 16 to provide additional disk surface for
storing greater amounts of data. The resulting combination is
referred to herein as a motor/disk assembly or as a disk pack
102.
Multiple data storage disks 16 can be mounted on the rotatable hub
98 in vertically and substantially equally spaced relations. One or
more bearings 104 are disposed between a motor or spindle shaft 106
and the rotatable hub 98, which is disposed about and rotatable
relative to the spindle shaft 106. Electromagnetic forces are used
to rotate the hub 98 about the stationary shaft 106 at a desired
velocity. Rotational movement of the hub 98 is translated to each
of the disks 16 of the disk pack 102, causing the disks 16 to
rotate with the hub 98 about the shaft 106.
The disks 16 are rotated about the shaft 106 at a high rate of
speed, and consumer demand for quicker data retrieval can result in
increased rotational speed of the hub 98 and the disks 16 to
provide reduced time in accessing data. Even minor imbalances of
the rotating motor/disk assembly 102 can generate significant
forces that can adversely affect the ability to accurately position
the head 36 relative to the desired track of the corresponding disk
16 while reading from or writing to the disk 16. Excessive
imbalance can degrade the disk drive performance not only in terms
of read/write errors, but also in terms of seek times. Excessive
imbalance may result in an undesirable acoustic signature and may
even result in damage or excessive wear to various disk drive
components.
The inner diameter 18 of each disk 16 is slightly larger in
diameter than an outer periphery of the spindle motor hub, or
rotatable hub 98, in order to allow the disks 16 to slip about the
spindle motor hub 98 during installation. During assembly, the
disks 16 may be positioned in an inexact concentric manner about
the spindle motor hub 98. In fact, in some instances, the disks 16
may be intentionally biased against the spindle motor hub 98. This
inexact concentric relationship between the disk 16 and the motor
hub 98 results in the disk pack 102 becoming imbalanced. This
imbalance can be manifest in at least two respects.
First, the rotating mass of each disk 16 results in a centrifugal
force radially extending in a direction from the axis of rotation
24 in a plane orthogonal to the axis of rotation 24 that includes
the axis of rotation 24. This can be referred to as a single plane
or "static" imbalance. Second, the same centrifugal force also
results in a moment about an axis extending from the axis of
rotation 24 in a plane orthogonal to the axis of rotation through
the axis of rotation 24. This can referred to as a dual plane, two
plane, or "dynamic" imbalance.
Balancing of the disk pack 102 is preferably conducted, for
example, by the manufacturer or during an assembly process, prior
to shipping the drive 10 to the consumer. Single plane balancing of
the disk pack 102 can include attaching one or more weights to one
side of the disk pack 102. Not all imbalances may be alleviated to
the desired degree by balancing within a single plane. Dual plane
balancing of the disk pack 102 can be achieved by attaching one or
more weights at two different elevations along the axis 24
corresponding with vertically spaced reference planes in an attempt
to improve upon the potential inadequacies of a single plane
balance.
Balancing the disk pack 102 can be accomplished by attaching one or
more weights to a central portion of the disk pack 102. For
example, as illustrated in FIG. 2, the disk pack 102 can have a
portion that holds the one or more weights or to which the one or
more weights attach. FIG. 2 illustrates a disk pack 102 having a
rotatable hub 98 that includes a disk clamp 100 having a plurality
of disk clamp apertures 110 positioned circumferentially about a
central portion of the disk pack 102.
Another source of vibrations caused during operation of the disk
drive 10 can be rotation of the actuator 28 about the axis of
rotation 40. A pivot shaft 120 preferably defines the axis of
rotation 40 about which the actuator 28 rotates. As the actuator 28
rotates from the parked position to a position over the disks 16,
the initiation of movement from its original stationary position
and as the actuator 28 stops at the desired position over the disks
16 can create various vibration modes that can adversely affect
performance of the disk drive 10. For example, one vibration mode
includes the actuator Butterfly mode (BFM). Modes of vibration can
also be encountered as the actuator 28 shifts and moves over the
disks 16 during operation of the disk drive 10.
One method of reducing the adverse effects generated by vibrations
due to operation of the actuator 28 is to modify the connection
between the pivot shaft 120 in the actuator 28.
FIG. 3 illustrates an exploded view of an actuator 28. The actuator
28 preferably includes an actuator bore 122 that is preferably
positioned substantially concentrically with the pivot shaft 120 so
as to rotate about the axis of rotation 40. The actuator bore 122
preferably includes a pivot inner surface 124 that defines a
substantially cylindrical surface.
A pivot bearing cartridge 38 is positioned over the pivot shaft
120, and the bearing cartridge 38 provides relative rotational
movement between the pivot shaft 120 in the actuator 28. In order
to secure the actuator 28 to the pivot bearing cartridge 38, a
tolerance ring 130 is provided and is pressfit between the bearing
cartridge 38 in the actuator 28. The tolerance ring 130 includes an
inner surface 132 that engages the bearing cartridge 38 and an
outer surface 134 that engages the pivot inner surface 124.
Positioned about the outer surface 134 of the tolerance ring 130
can be one or more contact members 136 that provide areas of
contact between the tolerance ring 130 and the pivot inner surface
124.
With reference to FIGS. 4 and 5, multiple bearing cartridges 38 can
be used for various applications depending on the desired
performance of the bearing cartridge 38. The bearing cartridge 138
includes a bearing line 140 that extends in a direction
substantially transverse to the axis of rotation 40. The bearing
line 140, in some embodiments, defines a line or a plane, about the
axis of rotation 40, that is aligned with pivots or bearings 142 of
the bearing cartridge 38. A pivot bearing span 144 is a distance
between bearing lines 140 of a bearing cartridge 38 that are
positioned along the axis of rotation 40. Some applications include
a bearing cartridge 38 with pivots 142 position along the axis of
rotation 40 such that one bearing line 140 is positioned adjacent a
pivot shaft base 146, and another bearing line 140 is spatially
positioned along the axis of rotational 40.
In some applications, it is desirable to use bearing cartridges 38
that include relatively larger pivot bearings 142. For example, in
some instances, using larger pivot bearings 142 can achieve greater
performance of the actuator 28 in connection with various vibration
modes. As larger pivot bearings 142 are used, the pivot bearing
span 144 can decrease, as reflected in FIG. 5 relative to FIG. 4.
As the pivot bearing span 144 changes, the contact members 136 of
the tolerance ring 130 preferably accommodate the span 144
changes.
FIG. 6 illustrates a schematic view of the coupling between a pivot
shaft 120 and an actuator 28. Positioned circumferentially about
the pivot shaft 120 is the bearing cartridge 38, which provides
relative rotational movement between the pivot shaft 120 and the
actuator 28 about the axis of rotation 40. The actuator 28 is
coupled to the bearing cartridge 38 by a tolerance ring 130 that is
pressfit between the pivot bearings 142 of the bearing cartridge 38
and the pivot inner surface 124 of the actuator 28.
Positioned along the tolerance ring outer surface 134 are one or
more contact members 136 that are raised from the tolerance ring
outer surface 134 by one or more chamfers, which can include an
outer chamfer 150 and an inner chamfer 152. The contact members 136
can be aligned with a respective bearing line 141 when the
tolerance ring 130 is positioned in the disk drive 10.
When the tolerance ring 130 is positioned between the bearing
cartridge 38 and the actuator 28, the tolerance ring 130 is
preferably elastically deformed along at least a portion of at
least one of the outer chamfer 150, the inner chamfer 152, and the
contact number 136 to provide a compliant coupling between the
bearing cartridge 38 and the actuator 28.
FIG. 7 illustrates embodiments of a tolerance ring 130 that is used
to couple an actuator 28 to a bearing cartridge 38 for providing
relative rotational movement between the actuator 28 and the pivot
shaft 120 about the axis of rotation 40. In one embodiment, the
tolerance ring 130 includes an outer chamfer 150 that it extends
from the outer surface 134 to the contact member 136 at a steeper
angle than the inner chamfer 152 extends from the outer surface 134
to the contact member 136. In some embodiments, the inner chamfer
152 is elastically deformed to a greater extent than that of the
outer chamber 150 when the tolerance ring 130 is positioned within
the disk drive 10.
The tolerance ring 130 can include asymmetric bump chamfers that
shift the contact area between the tolerance ring 130 and the pivot
inner surface 124 of the actuator 28, and the ring 130 enables
wider contact between the pivot bearings 142 and the pivot inner
surface 124 along the bearing line 144. This construction of the
tolerance ring 130 can improve performance of the disk drive,
including with respect to butterfly mode frequency, pivot rocking
amplitude, and pivot friction variation. For example, a tolerance
ring having symmetric chamfers has a BFM at 7600 Hz, while the BFM
frequency is shifter higher by about 15.8% to about 8800 Hz by
providing a tolerance ring having asymmetric chamfers. This
increase in BFM frequency enables higher actuator bandwidth, and
higher actuator bandwidth leads to higher performance disk drives
10, when considering higher capacities and faster read/write
processes.
In one embodiment, the tolerance ring 130, with asymmetric chamfers
150, 152, generates a higher stiffness along the outer chamfer 150
then the inner chamfer 152. In one embodiment, the outer chamfer
150 can extend from the outer surface 134 of the tolerance ring 130
to the contact member 136 at an angle between about 15.degree. and
about 45.degree.. In one embodiment, the outer chamfer 150 can
extend from the outer surface 134 to the contact member 136 at an
angle of about 24.degree.. In some embodiments, the outer chamfer
150 can extend from the outer surface 134 to the contact member 136
at an angle less than about 15.degree., and in some embodiments,
the outer chamfer 150 can extend from the outer surface 134 to the
contact member 136 at an angle greater than about 45.degree..
In one embodiment, the inner chamfer 152 can extend from the outer
surface 134 to the contact member 136 at an angle between about
5.degree. and about 35.degree.. In one embodiment, the inner
chamfer 152 can extend from the outer surface 134 to the contact
member 136 at an angle of about 17.degree.. In some embodiments,
the inner chamfer 152 can extend from the outer surface 134 to the
contact member 136 at an angle less than about 5.degree., and in
some embodiments, the inner chamfer 152 can extend from the outer
surface 134 to the contact member 136 at an angle greater than
about 35.degree..
In one embodiment, the disk drive 10 can include an actuator
assembly having a rotation axis 40 that is configured to rotate
about the axis 40. The drive 10 can include a bearing 38 that is
configured to provide rotational movement of the actuator assembly
about the axis 40. The drive 10 can also include a substantially
cylindrical tolerance ring 130 having an internal wall and an
external wall, and the tolerance ring 130 can be configured to
engage the bearing 38 along the internal wall. The tolerance ring
130 can also have a contact member 136, for engaging the actuator
assembly, along the external wall. The contact member 136 can have
a contact surface 154, protruding outward from the external wall,
and the contact surface 154 can be connected to the external wall
by two angulated walls, or chamfers 150, 152, that extend on
opposing ends of the contact surface 154. In one embodiment, the
two angulated walls, or chamfers 150, 152, extend from the external
wall to the contact surface 154 at different angles.
In one embodiment, the tolerance ring 130 includes a bottom edge
156 and a top edge 158, and the contact member 136 is positioned
along the external wall closer to one of the bottom edge 156 and
the top edge 158. In some embodiments, a first angulated wall of
the two angulated walls is positioned closer to the one of the
bottom edge 156 and the top edge 158 than a second angulated wall
of the two angulated walls. Some embodiments provide that the first
angulated wall extends from the external wall at a greater angle
than the second angulated wall. Some embodiments provide that the
first angulated wall extends from the external wall at an angle of
from about 15.degree. to about 45.degree., and some embodiments
provide that the second angulated wall extends from the external
wall at an angle of from about 5.degree. to about 35.degree.. In
some embodiments, the contact surface extends in a direction that
is substantially parallel to the external wall, and in some
embodiments, the contact surface extends is a direction that is
substantially parallel to the axis of rotation 40.
The tolerance ring can include a plurality of contact members 136
along the outer surface 134. In some embodiments, the plurality of
contact members are positioned circumferentially about the
substantially cylindrical tolerance ring. In some embodiments, the
plurality of contact members define an annular contact region about
the external wall of the tolerance ring. In some embodiments, the
tolerance ring 130 defines a ring axis, which can be contiguous
with or substantially identical to, the axis of rotation 40 when
the ring 130 is assembled in the drive 10, and the plurality of
contact members 136 can be positioned at different locations along
the axis 40. Some embodiments provide that the bearing 38 includes
a ball bearing, which can be contained within or defined by the
pivot bearing 142, and the contact member 136 can be positioned
adjacent the ball bearing when the tolerance ring 130 is positioned
between and engages the bearing and the actuator assembly.
In one embodiment, a tolerance ring for a disk drive includes a
substantially cylindrical body 131 having an internal surface 132
and an external, or outer, surface 134. The tolerance ring can be
configured to be positioned about, and to engage along the internal
surface 132, a rotational bearing 38, the cylindrical body defining
an axis 133, which can be contiguous with an axis of rotation 40.
The tolerance ring 130 can also include a contact member 136
positioned along the external surface 134, and the contact member
can include a contact surface 154 that protrudes outward from the
external surface 134 such that the contact surface 154 is spaced at
a greater radial distance from the axis 133 than the external
surface 134. The contact member 136 can be connected to the
external surface 134 by a first angulated arm 150 and a second
angulated arm 152. In one embodiment, the first and second
angulated arms 150, 152 extend from the external surface 134 to the
contact surface 154 at different angles.
Some embodiments provide that the first angulated arm 150 is
positioned closer to one of a bottom edge 156 of the ring and a top
edge 158 of the ring 130 than the second angulated arm 152. The
first angulated arm can extend, in some embodiments, from the
external surface 134 at a greater angle than the second angulated
arm 152. Some embodiments provide that the ring include a plurality
of contact members 136, and the plurality of contact members 136
can be positioned at different locations along the ring axis 40. In
some embodiments, the plurality of contact members 136 form at
least two annular contact regions 160 about the ring 130, the two
contact regions 160 being spaced along the ring axis 133.
The description of the invention is provided to enable any person
skilled in the art to practice the various embodiments described
herein. While the embodiments have been particularly described with
reference to the various figures and disclosure, it should be
understood that these are for illustration purposes only and should
not be taken as limiting the scope of the inventions.
There may be many other ways to implement the embodiments. Various
functions and elements described herein may be partitioned
differently from those shown without departing from the spirit and
scope of the disclosure. Various modifications to these embodiments
will be readily apparent to those skilled in the art, and generic
principles defined herein may be applied to other embodiments.
Thus, many changes and modifications may be made to embodiments, by
one having ordinary skill in the art, without departing from the
spirit and scope of the disclosure.
A reference to an element in the singular is not intended to mean
"one and only one" unless specifically stated, but rather "one or
more." The term "some" refers to one or more. Any headings and
subheadings are used for convenience only, do not limit the
disclosure, and are not referred to in connection with the
interpretation of the description of the disclosure. All structural
and functional equivalents to the elements of the various
embodiments described throughout this disclosure that are known or
later come to be known to those of ordinary skill in the art are
expressly incorporated herein by reference and intended to be
encompassed by the disclosure. Moreover, nothing disclosed herein
is intended to be dedicated to the public regardless of whether
such disclosure is explicitly recited in the above description.
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